This invention relates to the field of vending machines and, more particularly, to an improved control device for the dispensing mechanism in a vending machine.
Various types of dispensing mechanisms for vending machines have been used in the prior art depending on the type of food products or goods being vended. One well known type of dispensing mechanism uses a flapper device to dispense rectangular or cube shaped paper cartons containing a beverage or other liquid.
The basic construction of a flapper type dispensing mechanism is shown in commonly assigned U.S. Pat. No. 4,542,834, the disclosure of which is incorporated herein, in its entirety, by the foregoing reference thereto. This type of dispensing mechanism includes a rotating shaft which extends vertically into the storage area of the vending machine to divide the storage area into two vertical rows or columns stacked with vending articles. A control plate is fixed on the lower end of the rotating shaft and controls the operation of a pair of flappers positioned below the two vertical rows of articles. As the flappers open and close upon rotation of the shaft, the lowermost articles in the rows are dispensed.
During the dispensing operation, the articles stacked above the lowermost article are held in position by a holding apparatus. The holding apparatus may be connected to the rotating shaft and be automatically positioned by the shaft to hold the upper articles in place, e.g., by pressing the articles against the interior of the vertical rows. Operation of the holding apparatus is, therefore, quite likely to result in some deformation of the outer shape of the articles. As a result of the deformation, smooth operation of the dispensing mechanism will be impaired. Moreover, the time for completely dispensing an article from the dispensing mechanism will also increase. Also, the rotating shaft is usually operated by a motor which is controlled by a timer device. Thus, if the dispensing operation takes too much time, the shaft will begin turning before the dispensed article has cleared the flapper into the discharge opening. As a result, the dispensing mechanism is likely to become jammed.
Further prior art dispensing mechanisms are usually provided with a protecting circuit which turns the motor off after a predetermined time period has passed. Though the motor is protected from damage by the protective circuit, the vending machine remains inoperative even when articles are still stored within the storage area.